with 6,000$ it is super hard to make it at 1 month But Some developers gain it Fast
Yes it's hard you need to be in higher level position in a company just to earn this. And in bitcoin, you must have a lot of source combining, trading, profit in ICOs and other source that you may know. I can't earn this much monthly but yes developers can easily earn this. It's either they are developers of ICO's or they are blockchain developers that has extensive programming skills.
I dont see anyway developers are different from the other people that are into BTC. Yes they make ICOs, but I thought when they create ICOs, people make investments and they return it back after a while. Well, I dont really know how this works cause Im not really into it. Trading can help, but you have to be careful cause youre likely to lose your money also.